/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: Z.YD
 * Date: 2025-07-13
 * Time: 6:31
 */
public class MyLinkedList implements MyList{
    static class ListNode {
        public int val;
        public ListNode next;

        public ListNode(int val) {
            this.val = val;
        }
    }

    public ListNode head;


    @Override
    public void addFirst(int data) {
        ListNode node = new ListNode(data);

        node.next = head;

        head = node;
    }

    @Override
    public void addLast(int data) {
        ListNode node = new ListNode(data);
        if(head == null) {
            head = node;
            return;
        }
        ListNode cur = head;
        while(cur.next != null) {
            cur = cur.next;
        }
        cur.next = node;
    }

    @Override
    public void addIndex(int index, int data) {
        int len = size();
        if(index < 0 || index > len) {
            System.out.println("index位置不合法");
            return;
        }
        if(index == 0) {
            addFirst(data);
            return;
        }
        if(index == len) {
            addLast(data);
            return;
        }
        ListNode cur = head;
        while(index - 1 != 0) {
            cur = cur.next;
            index--;
        }
        ListNode node = new ListNode(data);
        node.next = cur.next;
        cur.next = node;

    }

    @Override
    public boolean contains(int key) {
        ListNode cur = head;
        while(cur != null) {
            if(cur.val == key) {
                return true;
            }
            cur = cur.next;
        }
        return false;
    }

    @Override
    public void remove(int key) {
        if(head == null) {
            return;
        }
        if(head.val == key) {
            head = head.next;
            return;
        }
        ListNode cur = findNodeOfKey(key);
        if(cur == null) {
            return;
        }
        ListNode del = cur.next;
        cur.next = del.next;
    }

    public ListNode findNodeOfKey(int key) {
        ListNode cur = head;
        while(cur.next != null) {
            if(cur.next.val == key) {
                return cur;
            }
            cur = cur.next;
        }
        return null;
    }

    @Override
    public void removeAllKey(int key) {
        if(head == null) {
            return;
        }
        ListNode prev = head;
        ListNode cur = head.next;
        while(cur != null) {
            if(cur.val == key) {
                prev.next = cur.next;
                cur = cur.next;
            } else {
                prev = cur;
                cur = cur.next;
            }
        }
        if(head.val == key) {
            head = head.next;
        }
     }

    @Override
    public int size() {
        ListNode cur = head;
        int count = 0;
        while(cur != null) {
            count++;
            cur = cur.next;
        }
        return count;
    }

    @Override
    public void clear() {
        ListNode cur = head;
        while(cur != null) {
            ListNode curN = cur.next;
            cur.next = null;
            cur = curN;
        }
        head = null;
    }

    @Override
    public void display() {
        ListNode cur = head;
        while(cur != null) {
            System.out.println(cur.val + " ");
            cur = cur.next;
        }
        System.out.println();

    }
}
